1. Field of the Invention
This invention relates to an exchange system for universal handling of data in a PBX (Private Branch Exchange), a LAN (Local Area Network), public communications networks, or the like, and more particularly, to an exchange system comprising a function for carrying out voice data communications between networks of different types.
2. Description of Related Art
Networks used for carrying out communications within a local area include networks using a digital PBX and networks using a LAN, and the like.
Communications networks using digital PBX are provided with a plurality of time division switches. A telephone terminal or low-speed data terminal having a communications rate of 64 kbps or less is connected to time division switches, by means of a balanced cable, or the like. Voice data is converted into data in packet format and is exchanged between the time division switches. In other words, this type of network uses a circuit switching system.
In a LAN, data terminals having a communications rate of 1-100 Mbps are connected directly by means of stranded cables, optical cables, or the like. Each data terminal exchanges frame data in MAC (Media Access Control) format. In a LAN, since each terminal communicates directly using a MAC address and terminal number, it is not necessary to provide an exchange. In other words, a LAN is a connectionless switching system. A LAN is able to conduct communication of voice data by using an Internet telephone. In this form of communication, a personal computer acting as a LAN terminal executes software in accordance with communications protocols. These communications protocols are based, for example, on ITU-T Recommendations H.323.
With the spread of LAN systems, situations arise where both networks using digital PBX and Internet telephone networks exist conjointly within the same area. However, since these networks use different types of communications paths and exchange systems, as described above, conventionally, it has not been possible to integrate these networks.
It is an object of this invention to provide an exchange system for conducting voice data communications between networks having different types of communications paths and exchange systems.
In order to achieve this, the voice data exchange system according to this invention comprises: first connecting means for carrying out mutual exchange of voice data used in a relay circuit of a telephone network and MAC frames; second connecting means for carrying out mutual exchange of voice data used by voice network telephone and MAC frames; data network telephone using MAC frames; switching means provided with a port for accommodating the first connecting means, a port for accommodating the second connecting means and a port for accommodating data network telephone, for carrying out switching of the ports in accordance with a destination address contained in a MAC frame; and main control means for executing communications protocols for call origination processing, call reception processing and disconnection processing, by communicating with the first connecting means, the second connecting means and the data network telephone.